Conventionally, there has been publicly known, as a surface-mount-type semiconductor device with an electroformed frame, the structure processed from a substrate for semiconductor element mount having an island portion for mounting semiconductor element thereon and an electrode portion for achieving conduction toward the external that are electroformed on an electroconductive substrate, by, after mounting a semiconductor element onto the island portion, electrically connecting the semiconductor element and the electrode portion by way of wire bonding and resin-sealing them on the electroconductive substrate, removing the electroconductive substrate alone, and cutting the sealed body into individual pieces.
For example, Japanese Unexamined Patent Application No. 2005-026631 teaches a method for producing a substrate for semiconductor element mount that is configured to have, over on the entire surface on one side of a support member, peelable layers constructed of two layers, which are a Cr layer and a Ni—Co layer, on which a conductor pattern of a desired shape made of copper material is formed. Further, Document 1 teaches that a semiconductor device is produced from this substrate by, after resin-sealing a semiconductor chip, peeling the support member off the sealing resin upon cutting notches down to the interface between the Cr layer and the Ni—Co layer, removing the remaining Ni—Co layer by etching, and forming, on the uncovered surface of the conductor pattern, a metal layer designed to function as connecting terminals to other semiconductor devices.
Japanese Unexamined Patent Application No. 2009-055055 discloses that a substrate for semiconductor device mount is produced by plating, after surface activation treatment such as microetching, an uncovered surface of an electroconductive substrate with Au or Ag as a metal layer for instrumentation, electroforming an electroformed layer, as an electroformed product, which is to be an island portion and an electrode portion, and removing a resist mask layer from the electroconductive substrate. Further, Document 2 teaches that a semiconductor device is produced from this substrate by, mounting a semiconductor element on the island portion of the electroformed product, electrically connecting the semiconductor element and the electrode portion by way of wire bonding, resin-sealing the semiconductor element, the island portion, the electrode portion and bonding wires on the electroconductive substrate, to form a resin-sealed member, peeling the electroconductive substrate to take out the resin-sealed member, and cut the resin-sealed member into pieces.
Japanese Unexamined Patent Application No. 2011-198977 teaches that, in a case where the electroconductive substrate is constructed of a first metal layer made of Cu and a second metal layer made of Ni, since formation of a metal layer to for instrumentation would cause too strong adhesion, an oxide film of desired thickness is formed on the Ni surface of the second metal layer by way of natural oxidization or oxidation treatment, to give an appropriate adhesion between the Ni layer and the electroformed product.